Changes in cortical thickness in 6-year-old children open their mind to a global vision of the world.

Nicolas Poirel,Olivier Houdé,Arlette Pineau,Grégory Simon,Elise Leroux

doi:10.1155/2014/362349

Abstract

Even if objectively presented with similar visual stimuli, children younger than 6 years of age exhibit a strong attraction to local visual information (e.g., the trees), whereas children older than 6 years of age, similar to adults, exhibit a visual bias toward global information (e.g., the forest). Here, we studied the cortical thickness changes that underlie this bias shift from local to global visual information. Two groups, matched for age, gender, and handedness, were formed from a total of 30 children who were 6 years old, and both groups performed a traditional global/local visual task. The first group presented a local visual bias, and the other group presented a global visual bias. The results indicated that, compared with the local visual bias group, children with a global visual bias exhibited (1) decreased cortical thickness in the bilateral occipital regions and (2) increased cortical thickness in the left frontoparietal regions. These findings constitute the first structural study that supports the view that both synaptic pruning (i.e., decreased cortical thickness) and expansion mechanisms (i.e., increased cortical thickness) cooccur to allow healthy children to develop a global perception of the visual world.

Highlights

IntroductionAdults and children do not perceive the forest (i.e., global visual information) and the trees (i.e., local visual information)
Adults and children do not perceive the forest and the trees
The present study is the first to document variations in cortical thickness during the developmental window corresponding to a shift from a local visual processing bias to an adult-like global visual processing bias

Summary

Introduction

Adults and children do not perceive the forest (i.e., global visual information) and the trees (i.e., local visual information). Because the global level (e.g., the whole, the forest) can be predicted from the identity of the local level (e.g., the features, the trees) and viceversa in a real-word situation, experimental materials that included a global level that could be apprehended independently of the local level (and vice versa) were developed by Navon [2, 7]. These compound stimuli consisted of large global forms composed of small local elements (e.g., a global triangle composed of local circles; see Figure 1) that presented an elegant method for performing global/local studies. After the age of 6 years, children exhibit more exploratory eye movements than younger children, suggesting a shift from a local sampling strategy of visual information to a more exhaustive exploration of global visual stimuli [10, 11]

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